Your carbon's beginnings

Composite of images related to work on presolar onion cores at UM-StL. At top left is a cutaway schematic of a cool red giant like those which made many of the carbon atoms in you, top center shows some core-rim presolar graphite onions after slicing, top right shows a reverse contrast HRTEM image taken at UM-StL illustrating the presence of edge-on intersecting but unlayered graphene sheets, bottom left shows graphite layering in the wall of a terrestrial graphite onion, bottom center compares graphite and unlayered graphene electron diffraction patterns, and bottom right shows what a pentagonal defect in a graphene sheet does to its flatness.

Log-scale (in meters) mass-flow schematic for an asymptotic giant branch (AGB) star after dredge-up of carbon atoms from the s-process intershell.

At top center, the light gray dot represents a liquid carbon droplet which will on gradual cooling be solidified as unlayered graphene, and then coated with graphite. The black material represents graphite condensed as a solid, while the green dot refers to a carbide seed on which graphite is later deposited. The red arrows represent ejection by radiation pressure from the base of the photosphere.

The blue dot on the horizontal axis represents the earth's radius, the "dark yellow" dot our sun's radius, and the red dot the radius of earth's orbit. The indigo ovals represent "third dredge-up" events, associated with periodic helium-shell flashes, which bring recently made "s-process" atoms up into the convection zone.